SummaryThis study intends to give the reader explanations of attitudes regarding the importance of global warming issues and modification of behaviors in order to mitigate problems. Measurements of optimism, locus of control and self-esteem have been used as mediat-ing factors. Data is collected from Indonesia and Sweden through questionnaires.BackgroundGlobal warming problems are today one of the most important missions politicians together with scientists have to resolve, and this includes an economic division of re-sponsibility worldwide. Psychology has a huge role in order to understand and change individuals' attitudes toward global warming issues.ObjectiveOur purpose with the study is to explore cultural differences in attitudes regarding global warming, specifically regarding the importance of global warming issues and regarding modification of behaviors in order to mitigate problems.MethodWith the use of questionnaires a quantitative study was conducted in the two cultures Indonesia and Sweden. Measurements of individualism/collectivism, Locus of control, Optimism and Self-esteem were used as mediating variables between culture and attitudes regarding global warming.ResultIndonesian respondents found global warming issues to be more important, than Swedish respondents. Swedish respondents were more willing to modify their behavior in order to mitigate global warming problems, than Indonesian respondents.